If you have used a cutter with even a modest amount of detail you will have spent many an hour picking the left behind bits from the sticky mat. At first you will probably use your fingernails, but after a few sharp edged bits of paper or card slip up between your nail and your finger, and the yelp of pain that follows, you will start to look for an alternative.
I used s scalpel for a while, but it left a few rather deep nicks in the cutting mat, so I gave in and ordered one of these.
I have to say I'm am so happy that I did. It is easy to hold and use, and the bits just lift up into your waiting (and undamaged) fingertips making it so much easier to clean the mat ready for the next cut.
You want the 5th star?
Make it cheaper!